My first child was born too early cos of my liver problems. I had very high aspat and alat. What can I do to help my liver in pregnancy?

Antioxidants. If you dont have a form of hepatitis that needs treatment during pregnancy you can take milk thistle. It has a powerfull antioxidants properties and can protect your liver better.If you had elevated enzymes because of hellp syndrome then there is nothing that can be done to prevent that from recurring.
Diet. At this time, it is very important to stay away from alcohol or any over the counter drugs that can worsen liver function, such as ibuprofen. Natural, low-fat healthy diet will also help. More than anything, seeking competent care from a high risk obstetric specialist (perinatologist) will be very important.